Following the old timers’ trail I pulled alongside my traveling partner Clarence Wood. Following his lead, I tapped my snowmachine’s kill switch. Break time. As I unscrewed the cap of my thermos and poured steaming cups of coffee for us both, melting snow hissed on our mufflers. The upper Redstone valley stretched northward into a blue-white ache. Ahead lay Iviisaq Pass, known for its terrain-driven winds; and beyond, an expanse of treeless, unpeopled country, not so much as an inhabited cabin until the village of Anaktuvuk Pass, 200 more miles to the northeast. Our laden sleds, the sort once pulled by dogs, bore gas, food, and gear to sustain us for nearly double that distance. This was our first break since we’d set out from our village of Ambler, on the upper Kobuk, outward bound on a great loop that would carry us to Anaktuvuk, south to the Koyukuk, then…